VANCOUVER -- Data examining 64,000 births in B.C. over four years has found expectant mothers who live in "green" neighbourhoods delivered babies with higher birthweight.

On average, according to University of B.C. study author Dr. Michael Brauer, parents in those neighbourhoods can expect infants 45 grams heavier than their counterparts.

The population statistics were taken from Metro Vancouver, which Brauer said was already green all over with the exception of a few pockets, such as the downtown core.

Forty-five grams may not seem like a big difference, Brauer said.

"But you have to think of this for the whole population. What we're doing is shifting the whole population by 45 grams (by living green)," he said.

The most interesting finding, he said, was how the "psychological" perception of having greenery present was a boon to birthweight.

"We have these measures of air pollution and noise -- we found that that actually made very little difference," Brauer said.

"The other ways we think green may impact health are more psychological or social...there seems to be a psychological link, depending on contact with nature or seeing nature or seeing greeness -- there's a whole literature in psychology that supports that."

He added the next steps would be to figure out how greenery affects a person's mental health, given its visual impact to the human psychology.